scholarly journals Localisation of cryptochrome 2 in the avian retina

2021 ◽  
Author(s):  
Angelika Einwich ◽  
Pranav Kumar Seth ◽  
Rabea Bartölke ◽  
Petra Bolte ◽  
Regina Feederle ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Ganglion Cell Layer ◽  
Migratory Birds ◽  
Outer Nuclear Layer ◽  
Cell Nuclei ◽  
Compass Orientation ◽  
Core Components ◽  
Magnetic Compass Orientation ◽  
Cryptochrome 2 ◽  
Subcellular Level

AbstractCryptochromes are photolyase-related blue-light receptors acting as core components of the mammalian circadian clock in the cell nuclei. One or more members of the cryptochrome protein family are also assumed to play a role in avian magnetoreception, but the primary sensory molecule in the retina of migratory birds that mediates light-dependent magnetic compass orientation has still not been identified. The mRNA of cryptochrome 2 (Cry2) has been reported to be located in the cell nuclei of the retina, but Cry2 localisation has not yet been demonstrated at the protein level. Here, we provide evidence that Cry2 protein is located in the photoreceptor inner segments, the outer nuclear layer, the inner nuclear layer and the ganglion cell layer in the retina of night-migratory European robins, homing pigeons and domestic chickens. At the subcellular level, we find Cry2 both in the cytoplasm and the nucleus of cells residing in these layers. This broad nucleic expression rather points to a role for avian Cry2 in the circadian clock and is consistent with a function as a transcription factor, analogous to mammalian Cry2, and speaks against an involvement in magnetoreception.

scholarly journals A novel isoform of cryptochrome 4 (Cry4b) is expressed in the retina of a night-migratory songbird

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Angelika Einwich ◽  
Karin Dedek ◽  
Pranav Kumar Seth ◽  
Sascha Laubinger ◽  
Henrik Mouritsen
Keyword(s):  
Mrna Expression ◽  
Expression Pattern ◽  
Migratory Birds ◽  
Radical Pair ◽  
The Novel ◽  
Erithacus Rubecula ◽  
Compass Orientation ◽  
Additional Exon ◽  
Magnetic Compass Orientation ◽  
Migratory Songbird

Abstract The primary sensory molecule underlying light-dependent magnetic compass orientation in migratory birds has still not been identified. The cryptochromes are the only known class of vertebrate proteins which could mediate this mechanism in the avian retina. Cryptochrome 4 of the night-migratory songbird the European robin (Erithacus rubecula; erCry4) has several of the properties needed to be the primary magnetoreceptor in the avian eye. Here, we report on the identification of a novel isoform of erCry4, which we named erCry4b. Cry4b includes an additional exon of 29 amino acids compared to the previously described form of Cry4, now called Cry4a. When comparing the retinal circadian mRNA expression pattern of the already known isoform erCry4a and the novel erCry4b isoform, we find that erCry4a is stably expressed throughout day and night, whereas erCry4b shows a diurnal mRNA oscillation. The differential characteristics of the two erCry4 isoforms regarding their 24-h rhythmicity in mRNA expression leads us to suggest that they might have different functions. Based on the 24-h expression pattern, erCry4a remains the more likely cryptochrome to be involved in radical-pair-based magnetoreception, but at the present time, an involvement of erCry4b cannot be excluded.

scholarly journals Electromagnetic 0.1–100 kHz noise does not disrupt orientation in a night-migrating songbird implying a spin coherence lifetime of less than 10 µs

2019 ◽  
Vol 16 (161) ◽  
pp. 20190716 ◽  
Author(s):  
Dmitry Kobylkov ◽  
Joe Wynn ◽  
Michael Winklhofer ◽  
Raisa Chetverikova ◽  
Jingjing Xu ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Migratory Birds ◽  
Radical Pair ◽  
Coherence Time ◽  
Magnetic Compass ◽  
Radio Waves ◽  
Spin Coherence ◽  
Compass Orientation ◽  
Magnetic Compass Orientation ◽  
Migrating Birds

According to the currently prevailing theory, the magnetic compass sense in night-migrating birds relies on a light-dependent radical-pair-based mechanism. It has been shown that radio waves at megahertz frequencies disrupt magnetic orientation in migratory birds, providing evidence for a quantum-mechanical origin of the magnetic compass. Still, many crucial properties, e.g. the lifetime of the proposed magnetically sensitive radical pair, remain unknown. The current study aims to estimate the spin coherence time of the radical pair, based on the behavioural responses of migratory birds to broadband electromagnetic fields covering the frequency band 0.1–100 kHz. A finding that the birds were unable to use their magnetic compass under these conditions would imply surprisingly long-lived (greater than 10 µs) spin coherence. However, we observed no effect of 0.1–100 kHz radiofrequency (RF) fields on the orientation of night-migratory Eurasian blackcaps ( Sylvia atricapilla ). This suggests that the lifetime of the spin coherence involved in magnetoreception is shorter than the period of the highest frequency RF fields used in this experiment (i.e. approx. 10 µs). This result, in combination with an earlier study showing that 20–450 kHz electromagnetic fields disrupt magnetic compass orientation, suggests that the spin coherence lifetime of the magnetically sensitive radical pair is in the range 2–10 µs.

scholarly journals A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds

PLoS ONE ◽  
2007 ◽  
Vol 2 (9) ◽  
pp. e937 ◽  
Author(s):  
Dominik Heyers ◽  
Martina Manns ◽  
Harald Luksch ◽  
Onur Güntürkün ◽  
Henrik Mouritsen
Keyword(s):  
Migratory Birds ◽  
Brain Structures ◽  
Visual Pathway ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Magnetic Compass Orientation

Magnetic compass orientation of migratory birds in the presence of a 1.315�MHz oscillating field

2004 ◽  
Vol 92 (2) ◽  
pp. 86-90 ◽  
Author(s):  
Peter Thalau ◽  
Thorsten Ritz ◽  
Katrin Stapput ◽  
Roswitha Wiltschko ◽  
Wolfgang Wiltschko
Keyword(s):  
Migratory Birds ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Magnetic Compass Orientation

Auditory and Magnetic Compass Orientation in C57BL/6 mice

2006 ◽  
Author(s):  
John B. Phillips ◽  
R. Muheim ◽  
N. M. Edgar ◽  
K. S. Sloan
Keyword(s):  
Magnetic Compass ◽  
Compass Orientation ◽  
Magnetic Compass Orientation

Stability of the Synechococcus elongatus PCC 7942 circadian clock under directed anti-phase expression of the kai genes

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2605-2613 ◽  
Author(s):  
Jayna L. Ditty ◽  
Shannon R. Canales ◽  
Breanne E. Anderson ◽  
Stanly B. Williams ◽  
Susan S. Golden
Keyword(s):  
Circadian Clock ◽  
Expression Patterns ◽  
Phase Relationship ◽  
Synechococcus Elongatus ◽  
Cycle Period ◽  
Rhythmic Expression ◽  
Core Components ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Time Required ◽  
Pcc 7942

The kaiA, kaiB and kaiC genes encode the core components of the cyanobacterial circadian clock in Synechococcus elongatus PCC 7942. Rhythmic expression patterns of kaiA and of the kaiBC operon normally peak in synchrony. In some mutants the relative timing of peaks (phase relationship) between these transcription units is altered, but circadian rhythms persist robustly. In this study, the importance of the transcriptional timing of kai genes was examined. Expressing either kaiA or kaiBC from a heterologous promoter whose peak expression occurs 12 h out of phase from the norm, and thus 12 h out of phase from the other kai locus, did not affect the time required for one cycle (period) or phase of the circadian rhythm, as measured by bioluminescence reporters. Furthermore, the data confirm that specific cis elements within the promoters of the kai genes are not necessary to sustain clock function.

scholarly journals In Vivo Role of Phosphorylation of Cryptochrome 2 in the Mouse Circadian Clock

2014 ◽  
Vol 34 (24) ◽  
pp. 4464-4473 ◽  
Author(s):  
A. Hirano ◽  
N. Kurabayashi ◽  
T. Nakagawa ◽  
G. Shioi ◽  
T. Todo ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Cryptochrome 2

Lateralisation of magnetic compass orientation in silvereyes, Zosterops lateralis

2003 ◽  
Vol 51 (6) ◽  
pp. 597 ◽  
Author(s):  
Wolfgang Wiltschko ◽  
Ursula Munro ◽  
Hugh Ford ◽  
Roswitha Wiltschko
Keyword(s):  
Geomagnetic Field ◽  
Magnetic Compass ◽  
Compass Orientation ◽  
Directional Information ◽  
Zosterops Lateralis ◽  
Magnetic Compass Orientation ◽  
Directional Preference ◽  
The Right ◽  
The Brain ◽  
The Magnetic Field

The ability of migratory silvereyes to orient was tested in the geomagnetic field with one eye covered. Silvereyes using only their right eye were able to orient in migratory direction just as well as birds using both eyes. Using only their left eye, however, the birds did not show a significant directional preference. These data indicate that directional information from the magnetic field is mediated almost exclusively by the right eye and processed by the left hemisphere of the brain. Together with corresponding findings from European robins and indications for a similar phenomenon in homing pigeons, they suggest that a strong lateralisation of the magnetic compass is widespread among birds.

Sign in / Sign up

Export Citation Format

Share Document